Final Report Summary - FURIM (Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells)
The project FURIM focused on the development of new improved membrane materials. The entire concept of proton exchange membrane fuel cells (PEMFC) at elevated temperature depends to a large extent on the membrane. Two main ways to replace water have been suggested. Either the sulphonic acid side chains must be replaced with something more flexible or water (the proton shuttle) must be replaced with something with a lower vapour pressure. To date the latter approach has been most successful, in particular exemplified with the PBI / phosphoric acid system. The new development in the field of proton exchange membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100 degrees Celsius. Fundamental materials, technological units and an integrated high temperature PEMFC-based power system operated on low sulphur diesel were the focus the project.
As the key materials, polybenzimidazoles and partially fluorinated sulphonated arylene main-chain polymers have been synthesised with optimised procedures, based on which cross-linked ternary blend membranes have been prepared. After acid doping the membranes exhibit promising properties in an operating temperature range from 120 to 200 degrees Celsius. Systematic characterisations of the membranes were carried out, showing very much improved properties e.g. proton conductivity of up to 0.10 S/cm, extended chemical stability and good mechanical strength and flexibility.
Catalysts and gas diffusion layer materials were prepared and characterised. Different techniques have been developed and optimised for fabricating gas diffusion electrodes. The influence of a range of structural parameters on the behaviour of gas diffusion electrodes was investigated. High temperature gas diffusion layers (HT-GDL) were specified and manufactured with excellent chemical, mechanical, electrical, fluid properties. Based on the materials and techniques developed, gas diffusion electrodes and membrane-electrode-assemblies (MEAs) have been fabricated. Single cell performance has been achieved of 0.58 A cm-2 at a cell voltage of 0.6 V with reformate and air under 4/4 bar pressure, with the best performance of 0.68 mAcm^(-2) at 0.6 V at 5/5 bars of hydrogen and air. For the long term durability, a degradation rate of 5 µVh-1 was achieved under continuous operation with hydrogen and air at 150-160 degrees Celsius. By defining a failure as 10 % performance loss, this degradation rate corresponds to a lifetime of 12 000 hours.
A 2 kWel final stack was designed and built with internal manifolds and integrated internal cooling circuit. The stack was operational with both dry hydrogen and reformate fuel containing up to 1 % CO. A fuel processing system was developed for converting diesel into a hydrogen rich gas suitable for usage in the high temperature PEM fuel cell stack. The system consisted of a pre-reformer, a desulphurisation unit, a reformer and a medium temperature water gas shift reactor.
Based on HT-PEMFC modelling, system simulation as well as system safety study, efforts were made finally to integrate the fuel processors and the stack as well as control units. The project successfully ended up with an integrated proof-of-principle high temperature PEMFC system, showing the feasibility of a diesel-fuelled, APU like fuel cell power system.
Additional efforts were made to train young researcher in the field. The efforts include university teaching and experimental courses, symposia, workshops, summer (spring) schools, and project meetings.
The overall objectives of FURIM were:
1. development of new or modified proton conducting polymers and membranes operational temperatures from 150-200 degrees Celsius with high proton conductivity (up to 0.10 S/cm) extended chemical stability and good mechanical strength and flexibility;
2. development of catalysts, gas diffusion layers, electrodes and cells for both anode and cathode in the HT-PEMFC;
3. development of sealing and stack components capable of withstanding the high temperature in combination with the phosphoric acid that is stored in the membrane;
4. development of and construct a 2 kW stack using exclusively components developed and manufactured in the project;
5. development and manufacture of a reformer system including a diesel evaporator, a reformer, a shift reactor and a burner;
6. integration of the fuel cell stack in the reformer system and running it as one unit;
7. assist the development work by modelling and simulations;
8. devotion of a significant effort to training of young students and scientists in the field of fuel cells and related technologies.
The project was structured into 5 work blocks (WBs) and 12 allocated work packages (WPs):
- WB 0. Membranes and cells
- WB 1. Stack
- WB 2. Reforming and integration
- WB 3. Modelling, simulation
- WB 4. Training
- WB 5. Coordination.
The project was started with synthesis of temperature resistant polymers, i.e. polybenzimidazoles (PBI) and sulphonated partially fluorinated arylene polyethers (1b). Binary blend membranes were prepared by solution casting and further doped with phosphoric acid. This ternary membrane material was extensively characterised and used in the final stack.
In FURIM, gas diffusion layer materials, catalysts, electrodes and techniques for preparing MEAs have been developed. A sub-project of FURIM was to study direct methanol fuel cells based on the high temperature membrane.
Commercial steam reforming catalysts and high temperature water gas shift (HT-WGS) catalysts have been collected and evaluated. Both reforming and WGS catalytic burning catalysts have also been prepared with modified carrier materials and characterised with respect to their composition, BET surface areas, porosity, and catalytic activities. 10 lab-made catalysts and 6 commercially available ones were tested for steam reforming of completely desulphurised diesel and of diesel containing 10 ppm S. It was found that the decrease of the hydrogen production rate in the presence of sulphur does not exceed 20 % at the worst case whereas it is lower than 10 %. Lab-made nickel catalysts supported on alumina modified by barium, lanthanum and barium, or cerium oxides proved to be quite promising for steam reforming of the desulphurized diesel (10 ppm S) exhibiting comparable activities with several commercial catalysts.
The objectives of the last 12 months of the FURIM project were the integration of a pre-reformer, a desulphurisation unit, a reformer, a medium temperature water gas shift reactor, a high temperature PEM fuel cell stack and the control unit. This was done resulting in an integrated proof-of-principle high temperature PEM fuel cell system. The final system was then tested in the laboratory of HyGear. This work package and therefore also FURIM was finished with an operable fuel cell system producing 1,5 kW electrical power. The system showed the feasibility of diesel converted into hydrogen operating an APU like fuel cell system.
The training activities during this project were in main forms of:
(1) university level courses on the subject of hydrogen and fuel cell;
(2) organising international events of workshops and summer schools;
(3) education of PhD students and post-docs through project research; and
(4) active participation in international summer schools and other events.
As the key materials, polybenzimidazoles and partially fluorinated sulphonated arylene main-chain polymers have been synthesised with optimised procedures, based on which cross-linked ternary blend membranes have been prepared. After acid doping the membranes exhibit promising properties in an operating temperature range from 120 to 200 degrees Celsius. Systematic characterisations of the membranes were carried out, showing very much improved properties e.g. proton conductivity of up to 0.10 S/cm, extended chemical stability and good mechanical strength and flexibility.
Catalysts and gas diffusion layer materials were prepared and characterised. Different techniques have been developed and optimised for fabricating gas diffusion electrodes. The influence of a range of structural parameters on the behaviour of gas diffusion electrodes was investigated. High temperature gas diffusion layers (HT-GDL) were specified and manufactured with excellent chemical, mechanical, electrical, fluid properties. Based on the materials and techniques developed, gas diffusion electrodes and membrane-electrode-assemblies (MEAs) have been fabricated. Single cell performance has been achieved of 0.58 A cm-2 at a cell voltage of 0.6 V with reformate and air under 4/4 bar pressure, with the best performance of 0.68 mAcm^(-2) at 0.6 V at 5/5 bars of hydrogen and air. For the long term durability, a degradation rate of 5 µVh-1 was achieved under continuous operation with hydrogen and air at 150-160 degrees Celsius. By defining a failure as 10 % performance loss, this degradation rate corresponds to a lifetime of 12 000 hours.
A 2 kWel final stack was designed and built with internal manifolds and integrated internal cooling circuit. The stack was operational with both dry hydrogen and reformate fuel containing up to 1 % CO. A fuel processing system was developed for converting diesel into a hydrogen rich gas suitable for usage in the high temperature PEM fuel cell stack. The system consisted of a pre-reformer, a desulphurisation unit, a reformer and a medium temperature water gas shift reactor.
Based on HT-PEMFC modelling, system simulation as well as system safety study, efforts were made finally to integrate the fuel processors and the stack as well as control units. The project successfully ended up with an integrated proof-of-principle high temperature PEMFC system, showing the feasibility of a diesel-fuelled, APU like fuel cell power system.
Additional efforts were made to train young researcher in the field. The efforts include university teaching and experimental courses, symposia, workshops, summer (spring) schools, and project meetings.
The overall objectives of FURIM were:
1. development of new or modified proton conducting polymers and membranes operational temperatures from 150-200 degrees Celsius with high proton conductivity (up to 0.10 S/cm) extended chemical stability and good mechanical strength and flexibility;
2. development of catalysts, gas diffusion layers, electrodes and cells for both anode and cathode in the HT-PEMFC;
3. development of sealing and stack components capable of withstanding the high temperature in combination with the phosphoric acid that is stored in the membrane;
4. development of and construct a 2 kW stack using exclusively components developed and manufactured in the project;
5. development and manufacture of a reformer system including a diesel evaporator, a reformer, a shift reactor and a burner;
6. integration of the fuel cell stack in the reformer system and running it as one unit;
7. assist the development work by modelling and simulations;
8. devotion of a significant effort to training of young students and scientists in the field of fuel cells and related technologies.
The project was structured into 5 work blocks (WBs) and 12 allocated work packages (WPs):
- WB 0. Membranes and cells
- WB 1. Stack
- WB 2. Reforming and integration
- WB 3. Modelling, simulation
- WB 4. Training
- WB 5. Coordination.
The project was started with synthesis of temperature resistant polymers, i.e. polybenzimidazoles (PBI) and sulphonated partially fluorinated arylene polyethers (1b). Binary blend membranes were prepared by solution casting and further doped with phosphoric acid. This ternary membrane material was extensively characterised and used in the final stack.
In FURIM, gas diffusion layer materials, catalysts, electrodes and techniques for preparing MEAs have been developed. A sub-project of FURIM was to study direct methanol fuel cells based on the high temperature membrane.
Commercial steam reforming catalysts and high temperature water gas shift (HT-WGS) catalysts have been collected and evaluated. Both reforming and WGS catalytic burning catalysts have also been prepared with modified carrier materials and characterised with respect to their composition, BET surface areas, porosity, and catalytic activities. 10 lab-made catalysts and 6 commercially available ones were tested for steam reforming of completely desulphurised diesel and of diesel containing 10 ppm S. It was found that the decrease of the hydrogen production rate in the presence of sulphur does not exceed 20 % at the worst case whereas it is lower than 10 %. Lab-made nickel catalysts supported on alumina modified by barium, lanthanum and barium, or cerium oxides proved to be quite promising for steam reforming of the desulphurized diesel (10 ppm S) exhibiting comparable activities with several commercial catalysts.
The objectives of the last 12 months of the FURIM project were the integration of a pre-reformer, a desulphurisation unit, a reformer, a medium temperature water gas shift reactor, a high temperature PEM fuel cell stack and the control unit. This was done resulting in an integrated proof-of-principle high temperature PEM fuel cell system. The final system was then tested in the laboratory of HyGear. This work package and therefore also FURIM was finished with an operable fuel cell system producing 1,5 kW electrical power. The system showed the feasibility of diesel converted into hydrogen operating an APU like fuel cell system.
The training activities during this project were in main forms of:
(1) university level courses on the subject of hydrogen and fuel cell;
(2) organising international events of workshops and summer schools;
(3) education of PhD students and post-docs through project research; and
(4) active participation in international summer schools and other events.
